The invention relates to a pressure-regulating arrangement having the features of the precharacterizing clause of Patent claim 1.
It is known (DE 42 24 981 A1) to provide the flow (pressure line) of a fuel pump with a pressure regulator whose switching threshold lies close to the maximum flow pressure. The cutoff quantity/flow is used as a driving jet for a self-priming ejector. The flow takes priority during operation. A fuel filter is often also provided in the flow from the pump, and has to keep contaminants originating from the tank away from the carburettor or injection pump/nozzles. Arrangements of this type have been tried and tested in practice.
The return flow from the injection pump has also already been used as the driving jet for the self-priming ejector. However, attempts are made as far as possible to dispense with a return line, for reasons of cost and in order to reduce possible leakage points (compliance with emission regulations). Instead, it is intended to supply the injection installation with just the amount of fuel which is actually consumed.
A combination of a pressure buffer and a fuel filter has already been proposed (earlier Patent Application 196 27 741.8). There, however, it is only indicated schematically that a chamber through which flow passes and which has a variable volume can be put together with a filter, the flow pressure is controlled as a function of the instantaneous chamber volume, so that neither a return nor a cutoff line is needed.